After 25 years, I finally gather up enough courage to change old habits. For the 1st time, a non-Castrol dino product is poured into my sump. The new oil? Chevron Delo 400 15w-40 mineral. The car feels like it runs better already. Probably a superior base stock in the Chevron oil. If everything works out, I may not even bother to change to Schaeffer Supreme Syn Blend at the end of 2000 miles of Auto-Rx treatment. Chevron Delo 400 may just be good enough to do the job. Thanks to everybody on this site. Without you guys, I would never have thought to try Chevron.